As plant/animal diversity wanes, is microbial life changing too? A perilously 'profound ignorance'

In a paper published today, David S. Thaler of the University of Basel, Switzerland, and guest investigator at Rockefeller University's Program for the Human Environment (PHE), notes the well-documented, "clearly downward" trajectory of plant and , constituting "a key issue of the Anthropocene."

Whether change is underway also in the world of microbes—the tiniest cogs in planetary functioning—is "a complete unknown. We have no idea whether global microbial diversity is increasing, decreasing, or staying the same," says Dr. Thaler.

"Most tell us new facts. This is a different kind of paper; it does not answer anything but asks a new question," says Dr. Thaler.

"Socrates called ignorance of what we do not know 'profound ignorance." This kind of ignorance was also famously termed 'unknown unknowns' by former U.S. Defense Secretary Donald Rumsfeld. Today's paper identifies what is (or was, as of now) a biological 'unknown unknown.'"

Dr. Thaler points out that assessing plant and animal biodiversity involves counting different species within a given timeframe, and then comparing a subsequent count. By doing so, we learned that some species have recently become extinct, and many exist in fewer numbers, with an estimated one million at risk of extinction within decades.

Each colour represents a different type of microbe. The white material in the core represents the remnants of human tongue cells about which the microbes grow. Credit: Steven Wilbert, Gary Borisy, Forsyth Institute; Jessica Mark Welch, Marine Biological Laboratory

Each dot or filament is a bacterial cell and the different colors indicate different kinds of bacteria. The larger, ridged ovals are single-celled algae called diatoms. Credit: Tabita Ramirez-Puebla and Jessica Mark Welch, Marine Biological Laboratory.

Each dot or filament is a bacterial cell and the different colors indicate different kinds of bacteria. The larger, ridged ovals are single-celled algae called diatoms. Credit: Tabita Ramirez-Puebla and Jessica Mark Welch, Marine Biological Laboratory